System and method for assessing noise floor data using radio blocking performance

ABSTRACT

An electronic device includes communications circuitry configured to communicate with an assistance server. The electronic device transmits a spectrum access request to the assistance server and receives, in response, an available channel list ranked by respective aggregate noise floor metric values from the assistance server. The aggregate noise floor metric value for each channel in the ranked channel list is determined by the server to account for a location of the electronic device, noise from radio frequency devices, and an adjacent channel blocking profile of the communications circuitry.

TECHNICAL FIELD OF THE INVENTION

The technology of the present disclosure relates generally to wirelesscommunications and, more particularly, to a system and method fordetermining which of plural available channels to use based on potentialinterference and radio blocking performance.

BACKGROUND

Wireless networks and systems are becoming increasingly popular. Butwireless communications are constrained due to a lack of available,interference free spectrum that may be used for reliable communicationswithin a geographic area. Even if a channel is available for use undergoverning regulations, the channel may not be a good choice for theradio due to interference from other radio systems. For example, radiosthat use television white space (TVWS) are wideband radios capable ofoperating over a large range of frequencies (e.g., VHF and UHF channelranges). The behavior of these radios (also known as TV white space banddevices or TVBDs) is such that if the noise floor on an availablechannel is high enough, the radio cannot effectively use the channel.Devices operating on the same channel and devices operating on adjacentchannels play roles in creating potentially detrimental noise floor forTVBD radios and other radios susceptible to relative high noise floors.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an exemplary system for determining noisefloor at a location of an electronic device.

FIG. 2 is an exemplary graphical user interface displayed by theelectronic device.

FIG. 3 is a representative operational environment for the electronicdevice.

FIG. 4 is a flow diagram representing an exemplary method of determiningnoise floor.

FIG. 5 is a flow diagram representing an exemplary method of supportoperations carried out by an assistance server that communicates withthe electronic device.

FIG. 6 is a flow diagram representing an exemplary method of assessingthe amount of noise on various channels while considering the adjacentchannel blocking performance of the electronic device.

FIG. 7 is a representative graphical illustration of adjacent channelblocking capabilities for the electronic device.

FIG. 8 is a representative graphical illustration of noise floordetermination for UHF channels in the location of the electronic device.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments will now be described with reference to the drawings,wherein like reference numerals are used to refer to like elementsthroughout. It will be understood that the figures are not necessarilyto scale. Features that are described and/or illustrated with respect toone embodiment may be used in the same way or in a similar way in one ormore other embodiments and/or in combination with or instead of thefeatures of the other embodiments.

A. INTRODUCTION

Methods and systems for determining noise floor for a radio device as afunction of emissions by other radio devices and operational performanceof the radio device in question will be described. This information maybe of assistance in planning wireless communications since theinformation is indicative of the actual effects of interference onwireless communications and radio operations.

In this document, noise floor refers to noise induced by interference,and not necessarily thermal noise. This induced noise floor information,after accounting for adjacent channel blocking performance of the radiodevice, will be referred to as an aggregate noise floor metric. Theaggregate noise floor metric is determined for the location of the radiodevice (alternatively referred to as an electronic device) with theassistance of a server. In a typical embodiment, the electronic deviceis a device that engages in wireless communications and uses theaggregate noise floor metric information in making one or moreconfiguration determinations, such as a channel selection or an antennaconfiguration selection.

The electronic device operates within regulations governing theoperation of the electronic device. For example, to enhance theavailability and reliability of interference free spectrum, proceduresthat are governed by regulatory agencies (e.g., the FederalCommunications Commission (FCC) in the United States) have beendeveloped for allocating and governing spectrum use. In the U.S., forexample, the FCC licenses spectrum in a primary spectrum market toCommission licensees. A secondary market exists for the Commissionlicensees to sublease spectrum for use by other parties.

As another approach to making spectrum available to many users, somespectrum may be used without a license in a regulated spectrum sharingenvironment. For example, the FCC has eliminated analog television (TV)broadcasts in favor of digital TV broadcasts. This has freed spectrumchannels for use by unlicensed radio systems to offer various services,such as mobile communications and Internet access. In this context, thefreed spectrum is commonly referred to as TV white space but other typesof white spaces are possible. In the case of TV white space, the whitespace is comprised of unused TV spectrum between channel 2 and channel51 (corresponding to 54 MHz to 698 MHz).

To avoid interference with digital TV broadcasts and other incumbentsystems, such as wireless microphone systems, radios that use the TVwhite space are required to request and receive a channel map (alsoreferred to as a channel list) of available channels that may be usedfor the communications activity of the radio system. The requestingelectronic device is free to use any of the channels that are indicatedas being available in the channel list. Current regulations requirethese radio systems to request a channel list every twenty-four hours.Also, for portable or mobile radios, if the radio moves into a newlocation, a new request must be made. Other regulations on the radiosare present, such as transmitted power limits for different types ofradios.

Although various regulatory agencies have identified parameters for theuse of unlicensed and/or shared spectrum, such as TV white spaces, thereis room for improvement in the manner in which radio devices areinformed of available spectrum and make channel selection decisions. Inone embodiment, the below-described server provides channel lists ofavailable spectrum to radio devices based on aggregate noise floormetric to improve use of spectrum resources. The aggregate noise floormetric for each available channel is indicative of the quality of thechannel for use by the radio device. For instance, a channel may beunoccupied by a protected device and, therefore, available for use. Butnot all available channels have equal amounts of noise. Channels with arelatively high amount of noise, referred to as “grey spaces,” may notadequately support the wireless communications operations of some radiodevices, especially if the radio device is not capable of blocking thenoise.

In many instances, the most troublesome amount of noise is from radiosthat generate out-of-band emissions that affect available channels.Therefore, the noise floor for each channel may depend oncharacteristics of the device making the channel list request. Forexample, the ability of the electronic device to perform adjacentchannel blocking may affect aggregate noise floor metric results. Otherexemplary factors include, but are not limited to, antenna configurationand orientation of the electronic device.

For purposes of description, the electronic device will be described inthe context where the electronic device is a device that requestschannel lists to access spectrum used for wireless communications. Anexemplary device of this nature is a TV white space band device (TVBD).It will be appreciated, however, that the electronic device may beanother type of device, such as a network planning tool, a mobiletelephone, a computer (e.g., a laptop computer or a tablet computer), amobile WiFi hotspot device, a media player, a gaming device, a personaldigital assistant (PDA), an electronic book reader, etc. The electronicdevice may be fixed in location, such as a wireless access point, or maybe portable, such as some of the above-mentioned devices. It will beunderstood that each described electronic device may be a radio systemthat includes one, or more than one, radio device that is capable ofwireless communications. In the case of a radio system that includesplural devices capable of wireless communications, a supervising devicemay request a channel list for the entire radio system and select anoperational channel, and each device in the system will be controlled tooperate in accordance with the selected channel.

In the context of white spaces, the white spaces may be television whitespaces or some other form of useable spectrum that is interleaved withspectrum used by incumbent, licensed or existing users, even if thatspectrum is not referred to as white space by a governing regulatoryentity. It will be appreciated, however, that the techniques describedin this document may apply to other situations, including situationsthat do not involve the selection of an operational channel.

Aspects of the disclosed systems and methods are independent of the typeor types of radio devices that may use spectrum. As such, the systemsand methods may be applied in any operational context for wirelesscommunications, and wireless communications are expressly intended toencompass unidirectional signal transmissions (e.g., broadcasting of asignal for receipt by a device without response) and to encompassbidirectional communications where devices engage in the exchange ofsignals. The methods and systems may be applied to dumb and/or cognitiveradio devices. The methods and systems may be applied to licensed orunlicensed spectrum. Furthermore, the methods and systems are generic tomodulation schemes, harmonic considerations, frequency bands or channelsused by the radio devices, the type of data or information that istransmitted, how the radio devices use received information, and othersimilar communications considerations. Thus, the systems and methodshave application in any suitable environment.

In embodiments in this disclosure, the electronic device makes aggregatenoise floor metric determinations in conjunction with a server. Theserver may undertake other functions, such as responding to white spacechannel list requests with appropriate channel lists. Therefore, in someembodiments, the server may be considered a central white spaceregistration system.

B. SYSTEM ARCHITECTURE

Referring initially to FIG. 1, shown is a system that includes anelectronic device 10 and a server 12. The electronic device 10 istypically, but not necessarily, portable and has wireless communicationcapabilities. The server 12 communicates with the electronic device 10,as well as other devices to which the server 12 provides services. Theelectronic device 10 may include a noise floor assessment function 14and the server 12 may include a noise floor data service 16. The noisefloor assessment function 14 and noise floor data service 16 maycooperate with each other to assist the electronic device 10 assesschannel quality for various combinations of location, orientation, andantenna configuration. The electronic device 10 and the server 12 maycommunication through a network 18, such as the Internet.

Each of the noise floor assessment function 14 and the noise floor dataservice 16 may be embodied as a set of executable instructions (e.g.,code, programs, or software) that are respectively resident in andexecuted by the electronic device 10 and the server 12. The functions 14and 16 each may be one or more programs that are stored on respectivenon-transitory computer readable mediums, such as one or more memorydevices (e.g., an electronic memory, a magnetic memory, or an opticalmemory). In the following description, ordered logical flows for thefunctionality of the noise floor assessment function 14 and the noisefloor data service 16 are described. It will be appreciated that thelogical progression may be implemented in an appropriate manner, such asan object-oriented manner or a state-driven manner.

The electronic device 10 includes communications circuitry 20. In theillustrated exemplary embodiment, as part of the communicationscircuitry 20, the electronic device 10 includes a radio circuit 22 andan antenna assembly 24. The communications circuitry 20 may be used tocarry out various wireless communications functions, includingcommunicating with the server 12. In the exemplary case where theelectronic device 10 is a mobile telephone, the communications functionsmay include engaging in voice or video calls, and sending or receivingmessages (e.g., email messages, text messages, multimedia messages,instant messages, etc.), accessing the Internet, etc. The illustratedcomponents may represent one or more than one radio transceiver toenable the electronic device 10 to be able to communicate over varioustypes of network connections and/or protocols. For instance, theelectronic device 10 may be configured to communicate with a cellularcommunications network. Exemplary cellular communications network typesinclude, by are not limited to, networks operating in accordance withglobal system for mobile communications (GSM), enhanced data rates forGSM evolution (EDGE), code division multiple access (CDMA), widebandCDMA (WCDMA), integrated services digital broadcasting (ISDB), highspeed packet access (HSPA), or any other appropriate standard oradvanced versions of these standards. The cellular communicationsnetworks may be compatible with 3G and/or 4G protocols. Additionally,the electronic device 10 also may be configured to communicate withother types of networks, such as a packet-switched network. An exemplarypacket-switched network includes a network configured in accordance withIEEE 802.11 (e.g., IEEE 802.11a, IEEE 802.11b, or IEEE 802.11n), each ofwhich are commonly referred to as WiFi®. Another exemplarypacket-switched network includes a network configured in accordance withIEEE 802.16 (commonly referred to as WiMAX®).

With additional reference to FIG. 2, the gain profile of the antennaassembly 24 may be known. In the embodiment where the electronic device10 uses the antenna 24 for wireless communications and makes noise floordeterminations to improve the wireless communications, the gain profileis the gain profile for a known configuration of the antenna assembly24. In embodiments where the electronic device 10 is a network planningtool for assisting a network developer in deploying a separate radiodevice, the gain profile refers to a gain profile of the radio devicefor which planning is being made. That is, an actual gain profile of anyantenna assembly of the network planning tool may not be the same as thegain profile used for noise floor determination.

FIG. 2 represents an exemplary graphical user interface (GUI) 26 that isdisplayed on a display 28 of the electronic device 10. The exemplarydisplay 28 includes touch-screen functionality. In one embodiment, theGUI 26 displays a polar plot 30 of the gain of the antenna assembly 24.The gain is measured with respect to a bore sight of the antennaassembly 24, which is typically fixed relative to a housing 32 of theelectronic device 10. In the illustrated embodiment, the bore sight isaligned with a longitudinal axis (denoted by arrow 34) of the electronicdevice 10. Regardless of the relationship of the bore sight of theantenna assembly 24 and the electronic device 10, the bore sight will beconsidered always aligned with a known point of the antenna gain profilesuch as the zero angle of the profile. The gain may be represented bycurve 36 on the polar plot 30. Again, in the embodiment where theantenna assembly 24 is part of the electronic device 10 that determinesnoise floor, these characteristics of the antenna assembly 24 relate tothe electronic device 10 itself. In the embodiment where the electronicdevice 10 is a configuration planning tool for another device, then theantenna characteristic information virtually represents actual antennacharacteristics of the device for which planning is made.

The antenna assembly 24 may have a fixed gain profile, such as one of anomnidirectional (“omni”) antenna, a 2 decibel (dBi) antenna, a 4 dBiantenna, etc. In other embodiments, the gain (or at least thedirectivity of the antenna) is variable. For example, the antennaassembly 24 may be controlled to have a gain selected from two or morepredetermined gains, such as an omni gain, a 2 dBi gain, a 4 dBi gain,etc. In still another embodiment, the antenna assembly 24 may becontrolled to customize the gain. In one embodiment of customizing thegain, the gain may be variably selected among two or more predeterminedgains (e.g., an omni gain, a 2 dBi gain, a 4 dBi gain, etc.) or pointsbetween the predetermined gains. In the embodiment of FIG. 2, variablyselecting the gain in this manner may be achieved using a slider tool38. In another embodiment of customizing the gain, the gain may bespecified by the user. In the embodiment of FIG. 2, specifying the gainin this manner may be achieved by dragging portions of the curve 36 intoa desired gain configuration.

Each gain setting of the antenna assembly 24 is associated with acorresponding physical configuration of the antenna assembly 24. Theconfiguration of the antenna assembly 24 is adjusted using configurationcircuitry of the antenna assembly 24, such as a MEMS switching array. Inone embodiment, the electronic device 10 stores an antenna library 40 ina memory 42. The antenna library 40 contains data regarding each ofplural antenna configurations. The data for each configuration mayinclude, for example, configuration data to assist in appropriatelysetting the configuration circuitry and gain information. In oneembodiment, the gain information for each antenna configuration of theelectronic device 10 also is stored by the server 12 in a database 44.And, each antenna configuration in the antenna library 40 and thedatabase 44 may be associated with a corresponding antenna configurationidentifier (e.g., value). As will be described below, storing antennadata for the electronic device 10 in the server 12 may simplify noisefloor information requests transmitted by the electronic device 10 tothe server 12. For instance, as part of the request, the electronicdevice 10 may identify a relevant antenna configuration value from theantenna library 40 rather than transmit an entire gain profile sincegain profiles for various antenna configurations of the electronicdevice 10 are already known by the server 12.

Additional information about the antenna assembly 24 may be known andstored in the library 40 and/or in the database 44. Another exemplaryitem of information may be antenna polarization.

Other stored information about the communications circuitry 20 mayinclude the adjacent channel blocking characteristics of the electronicdevice 10. In embodiments where the communications circuitry 20 has morethan one configuration (e.g., gain setting), there may be adjacentchannel blocking characteristics corresponding to each configuration.Adjacent channel blocking attributes of the electronic device 10 will bediscussed in greater detail below.

Overall functionality of the electronic device 10 may be controlled by acontrol circuit 46 that includes a processing device 48. The processingdevice 48 may execute code stored in a memory (not shown) within thecontrol circuit 48 and/or in a separate (e.g., the memory 42) in orderto carry out the operations of the electronic device 10. For instance,the processing device 48 may be used to execute the noise floorassessment function 14. The memory 42 may be, for example, one or moreof a buffer, a flash memory, a hard drive, a removable media, a volatilememory, a non-volatile memory, a random access memory (RAM), or othersuitable device. In a typical arrangement, the memory 42 may include anon-volatile memory for long term data storage and a volatile memorythat functions as system memory for the control circuit 46. The memory42 may exchange data with the control circuit 46 over a data bus.Accompanying control lines and an address bus between the memory 42 andthe control circuit 46 also may be present.

The display 28 may be used to display visual information to a user.Also, the electronic device 10 may include a speaker 50 and a microphone52 to allow the user to carry out voice conversations. One or more userinterfaces 54, such as a keypad and/or a touch-sensitive inputassociated with the display 28, may be present to provide for a varietyof user input operations.

The electronic device 10 may further include one or more input/output(I/O) interface(s) 56. The I/O interface(s) 56 may include one or moreelectrical connectors for connecting the electronic device 10 to anotherdevice (e.g., a computer) or an accessory (e.g., a personal handsfree(PHF) device) via a cable, and/or for connecting the electronic device10 to a power supply. Therefore, operating power may be received overthe I/O interface(s) 56 and power to charge a battery of a power supplyunit (PSU) 58 within the electronic device 10 may be received over theI/O interface(s) 48. The PSU 58 may supply power to operate theelectronic device 10 in the absence of an external power source.

A position data receiver, such as a global positioning system (GPS)receiver 60, may be involved in determining the location of theelectronic device 10.

A compass 62 may be used to determine the orientation of the electronicdevice 10 and, more specifically, the direction (e.g., azimuth) of thebore sight of the antenna assembly 24. In one embodiment, the compassdirection is displayed on the display 28 as part of the GUI 26. Forinstance, a virtual compass 64 indicating orientation of the electronicdevice 10 may be displayed. The virtual compass 64 may be displayed inconjunction with the polar plot 30 of the antenna gain. In theillustrated embodiment, the virtual compass subscribes the polar plot 30to visually demonstrate the relationship between the displayed gain andorientation of the electronic device 10. As the electronic device 10moves, the virtual compass 64 may rotate around the polar plot 30. Inthe illustrated embodiment, the bore sight (arrow 34) points due north.It will be appreciated the azimuth of the antenna assembly 24 willchange with changes in orientation of the electronic device 10.Regardless of the visually displayed information, the electronic device10 is configured to determine the compass direction of the bore sight ofthe antenna assembly 24 and include this information in noise floorinformation requests transmitted by the electronic device 10 to theserver 12.

One or more motion sensors 65, such as accelerometers, may be used tosense movement of the electronic device 10. The motion sensors 65 may beused to determined inclination of the antenna assembly 24 (e.g., angleof the bore sight of the antenna assembly 24 with respect to horizontalor vertical inclination).

The server 12 may be implemented as a computer-based system that iscapable of executing computer applications (e.g., software programs),including the noise floor data service 16. The noise floor data service16 and the database 44 may be stored on a non-transitory computerreadable medium, such as a memory 65. In addition to storing antennagain information for the electronic device 10, the database 44 may storedata about high power transmitters that is used by the noise floor dataservice 16.

The memory 65 may be a magnetic, optical or electronic storage device(e.g., hard disk, optical disk, flash memory, etc.), and may compriseseveral devices, including volatile and non-volatile memory components.Accordingly, the memory 65 may include, for example, random accessmemory (RAM) for acting as system memory, read-only memory (ROM), harddisks, optical disks (e.g., CDs and DVDs), tapes, flash devices and/orother memory components, plus associated drives, players and/or readersfor the memory devices.

To execute the noise floor data service 16, the server 12 may includeone or more processors 66 used to execute instructions that carry outlogic routines. The processor 66 and the memory 65 may be coupled usinga local interface 68. The local interface 68 may be, for example, a databus with accompanying control bus, a network, or other subsystem.

The server 12 may have various input/output (I/O) interfaces 70 as wellas one or more communications interfaces 72. The interfaces 70 may beused to operatively couple the server 12 to various peripherals, such asa display 74, a keyboard 76, a mouse 78, etc. The communicationsinterface 72 may include for example, a modem and/or a network interfacecard. The communications interface 72 may enable the server 12 to sendand receive data signals, voice signals, video signals, and the like toand from other computing devices via an external network. In particular,the communications interface 72 may connect the server 12 to the network18.

In one embodiment, the server 12 may be configured to host thebelow-described services for the electronic device 10. In someembodiments, the services may include spectrum management functions,such as providing channel lists to qualified radio devices uponregistration and/or request of the radio devices so as to allow theradio devices to make use of spectrum for wireless communications. Also,while the providing of services may be fully automated, the server 12may host an Internet-style website for the various corresponding partiesto conduct initial enrollment with the server 12, conduct manualregistration if needed, access various tools and reports supplied by theserver 12, and so forth. For supplying the services, the server 12 maycollect spectrum usage information from various sources, including butnot limited to public databases, private databases and deployed radiodevices (e.g., in the form of spectrum sensing results). The databaseinformation may contain information about known spectrum users, such asincumbent spectrum uses (e.g., digital television stations, wirelessmicrophone systems, cable head end systems, etc.), licensed spectrumusers, or radio systems that are exempt from seeking channel mapinformation in order to operate.

C. NOISE FLOOR ANALYSIS

Available, interference-free spectrum for supporting wirelesscommunications is a scarce resource and the demand for wirelesscommunications is increasing. The following techniques assist in usingspectrum efficiently by facilitating dissimilar radio technologies toco-exist.

With additional reference to FIG. 3, the techniques will be described inan exemplary environment where low-powered unlicensed devices (e.g., theillustrated electronic device 10) and high-powered protected devices 80(e.g., television transmitters) share a common set of bands. As a morespecific example, the low-power devices may be broadband datatransceivers (e.g., TVBDs) that operate at about +30 dBm in white spacesthat are interleaved with channels used by television transmitters thatcan operate up to +90 dBm. The high-powered devices 80 operate inrespective protected areas. The protected areas are established toreduce interference to the operation of the respective devices 80 bylimiting the use of the channel on which the device 80 operates(referred to as the primary channel of the device 80) by other devicesin the protected area. In the illustrated example, there are fivehigh-powered devices 80 (identified as 80 a through 80 e), but there maybe more than or fewer than five devices 80 that have an effect on thenoise floor at the location of the electronic device 10.

The availability of certain frequencies, or white space channels, is afunction of time, channel use, and geographic area. This concept of ashared spectrum ecosystem presents little risk to the operationalcapability of the high-power devices 80 as the low-power devices tend tonot cause interference to reception of the high-power signals and do notengage in co-channel operations within protected areas. But the presenceof high-powered transmitters can be very disruptive to operation of thelow-power devices. By comparison, the high-power transmitters oftenbroadcast at about one megawatt (MW) and with high-elevation antennas,whereas the low-power devices typically rely on transmitters of aboutone watt or less and are deployed with lower elevation antennas.

The high-power transmitters operating in VHF and UHF frequencies have avast reach that affects the noise floor over very large areas (e.g.,hundreds of miles) for the low-power devices. The primary channel andout-of-band coverage of high-power transmitters (e.g. TV stations) canbe accurately predicted using empirically-derived path loss models, suchas R6602 and Longley Rice and out of band emissions profiles for variousmodulations schemes, such as 8-VSB modulation typically used fortelevision transmissions. From this information, the noise floor foreach available channel in the low-power device's geographic location maybe determined so that a channel with a relatively low induced noisefloor may be selected for use. The effect of the interference (or noise)from the high-powered devices may be further refined using informationabout the low-power device, such as antenna gain, pattern and azimuth,and noise sensing data. The server 12 may be considered a co-existencemanager due to its role in determining noise floor information andproviding the information to the electronic device 10 and other radiosystems. The information may be updated as conditions change due tomovement of devices or variations in channel use.

With additional reference to FIG. 4, illustrated are logical operationsto implement a method of determining noise floor carried out by theelectronic device 10 and a method of assisting in determining noisefloor carried out the server 12. The exemplary methods may berespectively carried out by cooperatively executing an embodiment of thenoise floor assessment function 14 and an embodiment of the noise floordata service 16. Thus, the flow diagram may be thought of as depictingsteps of one method carried out by the electronic device 10 and anothermethod carried out by the server 12. Although the flow chart shows aspecific order of executing functional logic blocks, the order ofexecuting the blocks may be changed relative to the order shown. Also,two or more blocks shown in succession may be executed concurrently orwith partial concurrence.

In block 82, the electronic device 10 collects information for a noisefloor data request and transmits the noise floor data request to theserver 12. Noise floor data requests under several operational scenariosare possible. One scenario is when the electronic device 10 makes noisefloor determinations for itself and for a currently used gain profileand antenna direction. In this scenario, the information may includelocation of the electronic device 10. The location of the electronicdevice 10 may be ascertained using GPS, although other locationdetermining techniques are possible. The information may further includethe configuration of the antenna assembly 24 and the direction (e.g.,compass direction) of the bore sight of the antenna assembly 24. Theconfiguration of the antenna assembly 24 may be specified in terms of anappropriate one of the antenna configuration values from the antennalibrary 40. In circumstances where the antenna configuration is a customconfiguration or not known to the server 12, the configuration of theantenna assembly 24 may be specified in terms of the gain profile of theantenna assembly 24 (e.g., a polar plot). The direction of the boresight of the antenna assembly 24 may be specified as a compassdirection. Other information may be provided, such as antennapolarization if not discernable from the antenna configuration value.

Other information in the noise floor data request may include dataregarding spectrum use conditions in the location of the electronicdevice 10 (e.g., sensed noise on one or more channels). For instance,the electronic device 10 may identify the channels on which theelectronic device 10 detects (or “sees”) transmission activity andcorresponding signal strengths. This data represents data of actualbroadcasts by other radio systems and may be used to adjust noise floorcalculations made by the server 12. Other exemplary feedback may includechannel metrics, such as sensed noise on one or more channels and/orpacket completion rate on one or more channels.

Another operational scenario is when the electronic device 10 makesnoise floor determinations for itself and for an antenna configurationthat is different than the current used antenna configuration.Determining noise floor for an antenna configuration that is differentthan the currently used antenna configuration may be performed toevaluate the different configuration in an attempt to improvecommunications performance. In this scenario, the information in thenoise floor data request may include the location of the electronicdevice 10 as well as the gain profile and antenna direction for whichnoise floor information is desired. The gain profile may be specified,for example, as an appropriate one of the antenna configuration valuesfrom the antenna library 40 or as the complete gain profile. Thedirection may be specified as the actual compass direction of the boresight of the antenna or, if the antenna direction is controllable,specified as an antenna direction for which noise floor information isdesired.

Another operational scenario is when the electronic device 10 is aplanning tool. In this scenario, the information in the noise floor datarequest is representative of the potential location and antennaconfiguration (gain profile and antenna direction) of a separate radiodevice. The location in the noise floor data request may be the actuallocation of the electronic device 10 if the electronic device 10 ispresent in the potential location for the radio device. Alternatively,the planning may take place from a remote location using, for example, acomputer as the planning tool. In this case, the location specified inthe noise floor data request may be selected from a map or specifiedusing other data entry technique to indicate the potential location ofthe electronic device 10. Additionally, the gain profile and antennadirection may represent a potential configuration of the radio devicefor which planning is made. The gain profile may be specified, forexample, as an appropriate one of the antenna configuration values fromthe antenna library 40 or as the complete gain profile.

In block 84, the noise floor data request is received by the server 12.In block 86, the server 12 processes the noise floor data request todetermine noise floor value for each of various channels according tothe information contained in the noise floor data request. The channelsfor which the noise floor values are determined may be channelsrequested by the electronic device 10. In other embodiments, thechannels may be each channel in a predetermined range of channels (e.g.,TVBD channels) that is available for use by the electronic device 10(e.g., channels that are not protected as being occupied by an incumbentuser or for some other reason). In another embodiment, the channels maybe each channel in a predetermined range of channels (e.g., TVBDchannels) regardless of use protections.

In block 88, the noise floor values that were determined in block 86 aretransmitted by the server 12 to the electronic device 10. In theembodiment where the server 12 determines a channel list for theelectronic device 10, the noise floor values are transmitted inconjunction with the channel list. In block 90, the noise floor valuesand, if applicable, the channel list are received by the electronicdevice 10.

In block 92, the electronic device 10 may select a channel for wirelesscommunications based on the received noise floor values and, ifapplicable, the channel list containing the identification of availablechannels. In one embodiment, the electronic device 10 automaticallyselects the channel without user involvement. The selected channel maybe the channel with the lowest noise floor value. In other cases, theselected channel may be selected using the noise floor values as one ofseveral weighted factors in a channel selection function. In otherembodiments, the channel selection may be made by the user of theelectronic device 10. For instance, as illustrated in FIG. 2, noisefloor values by channel may be displayed on the display 28. The user mayselect a channel by touch selecting the desired channel from thedisplayed list or by other user input.

New requests for noise floor values may be made at various times, suchas periodically or if the electronic device changes location, changesdirection, and/or changes antenna assembly 24 configuration. Also,several requests may be made for various antenna configurations toobtain noise floor values that are compared to one another to assist inselecting one of the antenna configurations for conducting wirelesscommunications. Also, depending on the circumstances, various potentialalternative locations may be evaluated using corresponding requests.

In one embodiment, the operations of the methods depicted in FIG. 4 arecarried out at the command of the user. This embodiment may be used whenthe electronic device 10 is a network planning tool or in othersituations where the user is interested in maximizing operationalperformance. In another embodiment, the operations of the methodsdepicted in FIG. 4 are carried out automatically and without involvementof the user of the electronic device 10. Automatic performance of themethods may occur periodically and/or when a significant change to thelocation of the electronic device 10, the direction of the electronicdevice 10 and/or the configuration of the antenna assembly 24 isdetected. The automatic performance of the methods may occur as abackground operation to maintain a relatively high degree of operationalperformance.

D. NOISE FLOOR VALUE DETERMINATION

With additional reference to FIG. 5, illustrated are exemplaryoperations carried out by the server 12 to determine the noise floorvalues as part of block 86 of FIG. 4. As indicated, the determination ofnoise floor values may be conducted as part of determining a channellist for the electronic device 10 or as part of a separate supportoperation for the electronic device 10.

In block 94, the server 12 commences the noise floor value determinationby identifying each high-power device 80 that is within a predeterminedthreshold distance from the electronic device 10. The threshold distanceis established to identify transmitters that have a reasonable chance ofcontributing to the noise floor at the location of the electronic device10. For instance, when calculating noise floor for channels in OrlandoFla., one may want to consider transmitters as far away as Miami Fla.(approximately 200 miles from Orlando) and Atlanta Ga. (approximately420 miles from Orlando). But there would be little need to considertransmitters in Cleveland Ohio (approximately 1,000 miles from Orlando).In one embodiment, the threshold distance is in the range of about 100miles to about 800 miles. In another embodiment, the threshold distanceis in the range of about 250 miles to about 500 miles. In still anotherembodiment, the threshold distance is about 300 miles.

Once the high-power devices 80 are identified, the identified high-powerdevices 80 are added to a list of considered devices, referred to as aStationList. Then, in block 96, a Hashtable is indexed by channelidentifier (e.g., channel number). The Hashtable is used to storecomputed field strength for each channel. In one embodiment, theHashtable contains all channels in the range of channels managed by theserver 12 and the following determinations are made for each of thesechannels. In another embodiment, the Hashtable contains the channelsthat are not protected in the location of the requesting electronicdevice 10 (e.g., the channels that are potentially available for use bythe requesting electronic device 10) and the following determinationsare made for each of these channels, but not the protected (hence,unavailable) channels. In another embodiment, the Hashtable containschannels that are specified by the electronic device 10 in the noisefloor data request. In another embodiment, the Hashtable contains thechannels within the tuning capacity of the electronic device 10.

A process loop is carried out to determine the field strength level foreach channel based on the contributions from each device 80 in theStationList. In the illustrated embodiment, the process loop starts inblock 98 where a determination is made as to whether the StationList isempty. If a negative determination is made in block 98, the logical flowproceeds to block 100. In block 100, processing is commenced for thefirst device 80 in the StationList.

At block 102, the processing includes determining in-band field strengthof the device 80 being processed at the location of the requestingelectronic device 10. The band for which the in-band field strength isdetermined is the operating channel (referred to by the designator “n”or as the primary channel) of the device 80 being processed. Thedetermination is made by computation using a path-loss model. Thepath-loss model may account for known information, such as one or moreof the distance between the location of the device 80 and the locationof the electronic device 10, terrain data, and antenna characteristicsincluding but not limited to antenna height for the device 80 and/orantenna height of the electronic device 10. Antenna height of theelectronic device 10 may be determined by the electronic device 10 usingan altimeter (not shown) or GPS data, and incorporated into the noisefloor data request. Alternatively, antenna height of the electronicdevice 10 may be the ground elevation at the location of the electronicdevice 10 (e.g., as determined from a terrain database). Alternatively,the antenna height may be assumed to be a predetermined height aboveground elevation at the location of the electronic device 10, or aheight specified in the request (e.g., if the electronic device 10 is ina building, the user may specify an approximate elevation above groundlevel or sea level at the current location).

Exemplary path loss models include F-curves, R6602, Raleigh fading, andLongley Rice, although other path loss models may be used. The path lossmodel may be predetermined, such as by user settings or by default. Inother embodiments, a path loss model may be selected for the device 80being processed in accordance with one or more considerations, such asthe type of terrain between the device 80 and the electronic device 10,distance between the device 80 and the electronic device 10,characteristics of the device 80 (e.g., transmitter type, antennaazimuth and/or height, transmit power, etc.), operating channel of thedevice 80, setting (e.g., urban or rural) of the device 80 and/or theelectronic device 10, or other consideration.

At block 104, the processing includes determining out-of-band fieldstrength of the device 80 being processed at the location of therequesting electronic device 10. The out-of-band field strengthdetermination is repeated for a predetermined number of adjacentchannels above the operating channel of the device 80 being processedand a predetermined number of adjacent channels below the operationchannel of the device 80. If the predetermined number of channels istwo, for example, then the out-of-band field strength of the device 80is determined for n−1, n+1, n−2, and n+2. The predetermined number ofchannels may be one, two, three, four, or some other number of channels.The out-of-band field strength for each channel may be calculated usingthe in-band field strength and reducing the in-band field strength by anamount determined in accordance with empirical data (e.g. an 8-VSBmodulation emissions profile) and/or regulatory requirements.

In most circumstances, an emission mask for the device 80 may be assumedand the emission mask drives the calculation of the out-of-band fieldstrength for each channel. In one embodiment, the same calculationapproach is used for each device 80. But some devices 80 filterout-of-band emissions better than other devices 80. If an emission maskor profile is known for the device 80 being processed, thecharacteristics of that device may be used in the calculation ofout-of-band field strength values.

Refinements to the values calculated in blocks 102 and/or 104 for theknown antenna properties for the electronic device 10 may be made atblock 106. Exemplary antenna properties considered include, but are notlimited to, antenna gain, azimuth (compass direction of the bore sightof the antenna assembly 24), height, inclination, and polarization. Therefinements may be made by applying the antenna properties as part ofthe path loss model used in the foregoing steps or by post-solutionalteration of the values determined in the foregoing steps. In therepresentative illustration of FIG. 3, the electronic device 10 pointsmore in the direction of device 80 a than, for example, device 80 e.Therefore, device 80 a may have a greater contribution to the noisefloor for the electronic device 10 than device 80 e, even though device80 e may be geographically closer and/or has a larger protected area.

In block 108, the field strength values resulting from block 106 forin-band emissions and out-of-band emissions are stored in thecorresponding channel indices of the Hashtable. Next, in block 110, thedevice 80 that was processed in the preceding blocks of the processingloop is removed from the StationList. The logical flow then returns toblock 98 to determine if all devices 80 in the StationList have beenprocessed. If so, a positive determination is made in block 98 and thelogic flow proceeds to block 112.

In block 112, if any signal strength sensing data is available from theelectronic device 10 or other sources, such as other radio devices thatare nearby the electronic device 10, then this sensing data may be addedto the Hashtable under the appropriate channel indices. In oneembodiment, the sensing data includes detected signals from contributorsother than those considered in the prior blocks so as to avoidunintended inflation of the amount of noise on any of the channels.

In block 114, the noise floor value for each channel in the Hashtable isdetermined. In one embodiment, the noise floor value for each channel iscalculated from the field strength values for the corresponding channelindex in the Hashtable. The calculation includes converting each fieldstrength value for the channel to power density and summing theresulting power density values. Field strength (also referred to assignal strength) is often expressed in dBuV/m, which is a unit favoredby broadcasters since it is easy to measure and allows for easycalculation of the receiver voltage for a standard antenna. Fieldstrength expressed in dBuV/m is converted to power density for freespace and expressed in dBm/m² using the conversion relationship ofequation 1.dBm/m²=dBuV/m−115.8  Eq. 1

The conversion relationship of equation 1 is derived from the powerdensity and field strength equation P_(D)=E²/Z₀, where P_(D) is powerdensity in W/m², E is the root-mean-square (RMS) value of the field involts/meter, and Z₀ is the free space characteristic impedance of 377Ω.

To sum values expressed in dBm (or dBm/m²), the values are converted tomW (or mW/m²) using the relationship of equation 2.mW=10^((dBm/10))  Eq. 2

Values expressed in mW may be added and, if desired, converted back todBm (or dBm/m²) using the relationship of equation 3.dBm=10*log₁₀(mW)  Eq. 3

The noise floor values resulting from block 114 are the valuestransmitted to the electronic device 10 in block 88 (FIG. 4).

D(i). First Prophetic Example

This example describes the noise contributions from a protected radiodevice 80 in what is typically the worst case scenario for TV whitespaceuse. For in-band noise, this scenario is when the requesting electronicdevice 10 is just outside the protected entity service contour of theradio device 80 where the noise contributions from the radio device 80are likely to be the highest.

Table 1 shows the contour field strength values at the protected contourfor television stations as established by the FCC.

TABLE 1 Protected Contour Contour Propagation Type of TV Station Channel(dBu) Curve Analog: Class A TV, LPTV, Low VHF (2-6) 47 F(50, 50)translator and booster High VHF (7-13) 56 F(50, 50) UHF (14-69) 64 F(50,50) Digital: Full service TV, Low VHF (2-6) 28 F(50, 90) Class A TV,LPTV, High VHF (7-13) 36 F(50, 90) translator and booster UHF (14-69) 41F(50, 90)

According to table 1, the highest amount of in-band noise from a digitaltelevision station that an electronic device 10 may expect to experienceis 41 dbuV/m, which is equal to −74.8 dbm/m². When adjusted by theeffective area of a typical receive antenna with 7.5 dbi of gain(effective area 0.18 m²) where 10*log (1 meter/0.18 meters) equals 7.4db at 470 MHz, this yields a received noise power of −82.2 dbm, which isa very noisy environment.

The out-of-band emissions generated by a high-power station areconsidered next. Using empirically-derived field data, it has beendetermined that the out-of-band noise generated by a TV station inadjacent 6 MHz channels can be as high as follows: about 45 db less thanthe in-band signal strength in immediately adjacent channels (n±1),about 50 db less than the in-band signal strength two channels above andbelow (n±2), about 55 db less than the in-band signal strength threechannels above and below (n±3), and about 60 db four less than thein-band signal strength channels above and below (n±4).

For the worst case scenario, the out-of band emissions typically arecaused by stations having a protected region in which the electronicdevice 10 is located. The in-band signal strength of these stations atthe location of the electronic device 10 may be as high as 100 dbuV/msince the electronic device 10 is within the protected entity servicecontour. Therefore, an available (un-protected) white space channel +/−2channels from a protected channel can yield a noise floor as high as 50dbuV/m (−65.8 dbm/m²), yielding a received noise power of −73.8 dbm (fora 7.5 dbi antenna). This amount of noise effectively renders thesechannels inoperative for wireless communication by the electronic device10. These channels may be considered “grey space” rather than whitespace.

D(ii). Second Prophetic Example

In this example, the requesting electronic device 10 is located in alocation where channels 14, 15, 18, and 19 are available. At thislocation, two televisions stations, referred to as TV1 and TV2,respectively operate on channels 16 and 17 and are within the thresholddistance for consideration as noise contributors to the requestingelectronic device 10. Sensing data is available at this location forchannel 19. At the time of the request, the sensed field strength valueis 17.8 dBuV/m.

In accordance with the foregoing process flow, TV1 (primary channel 16)and TV2 (primary channel 17) are added to the StationList. For purposesof this example, it will be assumed that the determined in-band fieldsignal strength level for TV1 is 95 dBuV/m. Each TV station emissionuses a filter to restrict emissions in adjacent channels, but emissionsare still present in adjacent channels. For purposes of the example, amask is applied where out-of-band emissions are determined to be 45 dbless than the in-band signal strength in immediately adjacent channels(n±1) and 50 db less than the in-band signal strength two channels aboveand below (n±2). Under these assumptions the out-of-band field strengthsdue to TV1 for channels 15 and 17 (n±1) are each 50 dBuV/m (95 dBuV/mminus 45 dBuV/m) and the out-of-band field strengths due to TV1 forchannels 14 and 18 (n±2) are each 45 dBuV/m (95 dBuV/m minus 50 dBuV/m).The field strength values for TV1 are stored in the Hashtable under theappropriate channel indices.

Similar field strength determinations are made for TV2, which operateson channel 17. For purposes of this example, it will be assumed that thedetermined in-band field signal strength level for TV2 is 90 dBuV/m.Using the same out-of-band calculation assumptions that were used forTV1, the out-of-band field strengths due to TV2 for channels 16 and 18(n±1) are each 45 dBuV/m (90 dBuV/m minus 45 dBuV/m) and the out-of-bandfield strengths due to TV2 for channels 15 and 19 (n±2) are each 40dBuV/m (90 dBuV/m minus 50 dBuV/m). The field strength values for TV2are stored in the Hashtable under the appropriate channel indices.

The sensing data for the location of the requesting electronic device 10(17.8 dBuV/m (6 MHz) in channel 19) is also stored in the Hashtableunder the index for channel 19. Table 2 represents an exemplaryHashtable for the values described in this example.

TABLE 2 Index Contributor 1 (TV1) Contributor 2 (TV2) Sensing DataChannel 14 45 — — Channel 15 50 40 — Channel 16 95 45 — Channel 17 50 90— Channel 18 45 45 — Channel 19 — 40 17.8

Table 3 shows the Hashtable of table 2 with the values converted todBm/m² and the sum of the values for each index.

TABLE 3 Contributor 1 Contributor 2 Index (TV1) (TV2) Sensing Data SumChannel 14 −70.8 — — −70.8 Channel 15 −65.8 −75.8 — −65.3 Channel 16−20.8 −70.8 — −20.7 Channel 17 −65.8 −25.8 — −25.7 Channel 18 −70.8−70.8 — −67.8 Channel 19 — −75.8 −98 −75.7

D(iii). Alternatives

There are a total 50 channels in TV white space. There are about 8,000broadcast television stations in the U.S. Processing and recording fieldstrength values for each of the channels can become processor intensivewhen there are a relatively large number of noise contributors toconsider. To reduce processing while minimizing sacrifices inperformance, the contributors considered by the server 12 may be limitedto high-powered devices 80 that operate on channels that are available(un-protected) at the location of the requested electronic device 10 andhigh-powered devices 80 that operate on channels adjacent to thechannels that are available (un-protected) at the location of therequested electronic device 10 by one channel increment (n±1) and by twochannel increments (n±2) (or another predetermined number of channelincrements from the available channel). Under this adjustment, theHashtable need only contain computed field strength values and sensingdata for available channels. For example, if only channel 17 and 19 areavailable at the requesting device's location, then only thosehigh-power transmitters operating on the available channels 17 and 19and the channels within the predetermined number of adjacent channelsabove and below the available channels are considered in the fieldstrength level computations. Any other high-power transmitters may beignored. If the predetermined number of adjacent channels above andbelow the available channels is two, then under the example where theavailable channels are channels 17 and 19 the channels adjacent channel17 within two channel increments are channels 15, 16, 18, and 19.Similarly, the channels adjacent channel 19 are 17, 18, 20, and 21. As aresult, the channels to be processed include the subset of channels 15,16, 17, 18, 19, 20, and 21, and processing of transmitters notbroadcasting on those channels may be ignored.

An additional or alternative change to reduce processing is to ignoretransmitters that do not have a significant effect on the noise floorlevel of the transmitter's primary channel and adjacent channels. As anexample, assume that there are 200 TV stations within a radius definedby the predetermined distance. Typically, not all of these stations willtransmit at a high-power level given their distance from the location ofthe requesting electronic device to have a significant effect on theprimary channel of the transmitter and the adjacent channels. Suchstations may be eliminated from consideration. In one embodiment, thetransmitters that are ignored are those transmitters that have acomputed field strength at their primary channel that is less than apredetermined threshold field strength threshold, regardless of thedistance between the transmitter and the requesting electronic device.In another embodiment, if transmit power at a predetermined distancefrom the location of the requesting electronic device falls below apredetermined field strength threshold, then this station is eliminatedfrom consideration.

E. AGGREGATE NOISE FLOOR METRIC DETERMINATION

The noise determinations from the preceding sections may affectdifferent radio devices in different manners based on the ability ofeach radio device to block out-of-band emissions from other spectrumusers. With additional reference to FIG. 6, illustrated is a flowchartdepicting an exemplary technique for assessing the amount of noise onvarious channels while considering the adjacent channel blockingperformance of the electronic device 10. The illustrated logicaloperations of FIG. 6 may be considered to depict a method that iscarried out by the electronic device 10 and a corresponding method thatis carried out the server 12. The exemplary methods may be respectivelycarried out by cooperatively executing an embodiment of the noise floorassessment function 14 and an embodiment of the noise floor data service16. Although the flow chart shows a specific order of executingfunctional logic blocks, the order of executing the blocks may bechanged relative to the order shown. Also, two or more blocks shown insuccession may be executed concurrently or with partial concurrence.

In block 116, the electronic device 10 transmits a spectrum accessrequest to the sever 12. In one embodiment, the spectrum access requestis a channel list request (e.g., a TVWS channel map request). In otherembodiments, the request is for spectrum access but in a form other thana channel list request. In still other embodiments, the request is fornoise floor data without spectrum access or channel availabilityinformation. In the following description, the described processing isfor the generation of a ranked channel list in response to a channellist request, but it will be understood that the processing will bemodified for the generation of alternative result sets.

The request of block 116 may include the identity and location of theelectronic device 10. In one embodiment, the adjacent channel blockingcapabilities of the electronic device 10 are transmitted as part of therequest. In other embodiments, the adjacent channel blockingcapabilities of the electronic device 10 are already known by the server12. In a typical embodiment, the adjacent channel blocking capabilitiesare for the make and model of the electronic device 10 as determined bythe manufacturer of the electronic device 10. In other embodiments, theadjacent channel blocking capabilities of the electronic device 10 aredetermined for the specific electronic device 10 or may be estimatedbased on known information for similar devices.

With additional reference to FIG. 7, shown is a representative graphicalillustration of adjacent channel blocking capabilities for theelectronic device 10. It will be understood that the adjacent channelblocking capabilities supplied to the server 12 need not be in graphicalform and may be in any appropriate data format. Typically, the blockingperformance profile is specified as adjacent channel desired toundesired (D/U) ratio (e.g., in dB) as a function of frequency. It willbe further understood that the adjacent channel blocking capabilitiesvary from electronic device to electronic device. The representativeexample of FIG. 7 shows D/U ratio (the Y-axis) as a function offrequency relative to the center frequency of a channel to which theelectronic device 10 is tuned. The graph of the adjacent channelblocking capabilities is dependent on the amount of signal attenuationby the electronic device 10 based on the departure of the frequency fromthe center frequency of the channel to which the electronic device istuned. The electronic device 10 may exhibit different adjacent channelblocking capabilities for different channels and/or for differentantenna configurations. In this case, the data relating to adjacentchannel blocking capabilities that is supplied to the server 12 willinclude these variations in performance so that determinations made bythe server 12 are appropriate for the channel undergoing analysis and/orfor the current or potential antenna configuration.

In block 118, the server 12 receives the request that was transmitted bythe electronic device 10 in block 116. In block 120, the server 12determines the channels that are available for use at the location ofthe electronic device 10. In addition, the server 12 determines thenoise floor for each channel at the location of the electronic device10. The noise floor determination may be made in any appropriate manner,such as by using one of the techniques described in the foregoingsections of this disclosure document. In other embodiments, the noisefloor is determined from measurements made by the electronic device 10and/or other nearby electronic devices. The noise floor determinationmay be made without regard to antenna configuration of the electronicdevice 10 or with consideration of the antenna configuration of theelectronic device 10 as described above.

With additional reference to FIG. 8, shown is a representative graphicalillustration of noise floor values for UHF channels (channels 14 through51) in the location of the electronic device 10. VHF channels (channels2-13) will have similar results. The amount of noise in terms ofinterferer power (the y-axis) is shown for each channel (the x-axis).

In block 122, the server 12 adjusts the noise floor values for eachchannel according to the adjacent channel blocking performance of theelectronic device 10 to determined an aggregate noise floor metric valuefor each channel. The aggregate noise floor metric value for eachchannel represents the noise environment for the electronic device 10that is created by other transmitters after considering the ability ofthe electronic device 10 to block or attenuate noise on channels aboveand below the channel being evaluated. In one embodiment, whendetermining the aggregate noise floor metric for each channel, theserver 12 considers noise and adjacent channel blocking performance ofthe electronic device 10 across all channels. In other embodiments, theserver 12 considers noise and adjacent channel blocking performance ofthe electronic device 10 for a predetermined number of adjacent channelsabove the channel being considered and a predetermined number ofadjacent channels below the channel being considered.

Each electronic device 10 is expected to have a different set ofco-channel and adjacent channel D/U ratios for effective operation. Inone embodiment, to determine the aggregate noise floor metric for achannel, the aggregate noise floor metric is calculated as a function ofradio sensitivity (RS), co-channel induced noise floor, a set ofweighting factors (WF), adjacent channel signal (ACS) (ACS being theinduced adjacent channel noise floor), and the D/U ratios. Noting thateach D/U ratio is typically a negative value, equation 4 sets forth onexemplary expression for calculating an aggregate noise floor metric fora channel where the two adjacent channels below and the two adjacentchannels above the channel are considered. Another number of adjacentchannels may be considered.Aggregate noise floor metric=(RS−co-channel induced noisefloor)+(WF_(n+1))×(RS−ACS_(n+1)−D/Uratio_(n+1))+(WF_(n−1))×(RS−ACS_(n−1)−D/Uratio_(n−1))+(WF_(n+2))×(RS−ACS_(n+2)−D/Uratio_(n+2))+(WF_(n−2))×(RS−ACS_(n−2)−D/U ratio_(n−2))  Eq. 4

Table 4 shows an exemplary set of D/U ratio values for various channels.It will be appreciated that the adjacent channel blocking performance ofthe electronic device 10 need not be symmetric about the channel forwhich the calculation is being made and/or may differ depending on thechannel for which the calculation is being made.

TABLE 4 Channel D/U Ratio n 0 n ± 1 −10 n ± 2 −15 n ± 3 −20

Next, in block 124, the server 12 ranks the available channels fromlowest aggregate noise floor metric value to highest aggregate noisefloor metric value. The channels with a relatively low aggregate noisefloor metric value are considered to be better for wirelesscommunications than channels with higher aggregate noise floor metricvalues. Therefore, ranking the channels in terms of indicators ofaggregate noise floor may assist the electronic device 10 selecting achannel that will deliver a high level of quality of service (QOS) forthe electronic device 10.

Referring to the graphical illustration of noise floor values in FIG. 8,channels 25 and 36 have the lowest noise floor values, followed bychannels 23, 16, 20 and 48. But after adjusting for adjacent channelblocking performance of the electronic device 10, this order may change.For instance, if the electronic device does not effectively block noisefrom channel 27, which has a relatively high interferer signal strength,then channel 25 may drop in rank compared to other channels (e.g.,channel 23) that have smaller amounts of interference on neighboringchannels. Therefore, in this example, it may be better for theelectronic device 10 to selected channel 23 over channel 25 for use inconducting wireless communications. Other considerations, such asexisting channel selections made by other TVBDs, may be considered whenranking the channels and/or selecting a channel for wirelesscommunications.

In block 126, the ranked channel list is transmitted from the server 12to the electronic device 10. The ranked channel list is received by theelectronic device 10 in block 128. Then, in block 130, the electronicdevice 10 selects a channel and carries out wireless communicationsusing the selected channel.

As an alternative to the illustrated logical flow of FIG. 6, the server12 may transmit the noise floor values and channel availabilityinformation to the electronic device 10. The electronic device 10 thenmay analyze the provided information in conjunction with the blockperformance of the radio device. Therefore, in one embodiment, theelectronic device 10 may determine the aggregate noise floor metricvalues and select a channel using the results of the analysis made bythe electronic device 10.

F. CONCLUSION

Although certain embodiments have been shown and described, it isunderstood that equivalents and modifications falling within the scopeof the appended claims will occur to others who are skilled in the artupon the reading and understanding of this specification.

What is claimed is:
 1. An electronic device, comprising: communicationscircuitry configured to communicate with an assistance server andcomprising an antenna assembly and a radio circuit, the communicationscircuitry having an adjacent channel blocking profile; and a controllerconfigured to transmit a spectrum access request to the assistanceserver, the spectrum access request including a location of theelectronic device, and the controller further configured to receive anavailable channel list ranked by respective aggregate noise floor metricvalues from the assistance server, the aggregate noise floor metricvalue for each channel in the ranked channel list determined to accountfor the location of the electronic device, noise from radio frequencydevices, and the adjacent channel blocking profile of the communicationscircuitry.
 2. The electronic device of claim 1, wherein the aggregatenoise floor metric value for each channel in the ranked channel list isfurther determined to account for a gain profile and direction of theantenna assembly.
 3. The electronic device of claim 1, wherein theelectronic device engages in wireless communications using thecommunications circuitry and the controller is further configured toselect an available channel from the ranked channel list for thewireless communications of the electronic device.
 4. The electronicdevice of claim 3, wherein the electronic device transmits the spectrumaccess request and makes the channel selection as background operationswithout involvement of a user.
 5. The electronic device of claim 1,wherein the noise from the radio frequency devices includes predictednoise floor from primary channel and out-of-band emissions of high-powerprotected transmitters.
 6. A method of identifying availablecommunication channels for use in wireless communications by anelectronic device, the electronic device including communicationscircuitry configured to communicate with an assistance server andcomprising an antenna assembly and a radio circuit, the communicationscircuitry having an adjacent channel blocking profile, comprising:transmitting a spectrum access request to the assistance server, thespectrum access request including a location of the electronic device;and receiving, from the assistance server, an available channel listranked by respective aggregate noise floor metric values, the aggregatenoise floor metric value for each channel in the ranked channel listdetermined to account for the location of the electronic device, noisefrom radio frequency devices, and the adjacent channel blocking profileof the communications circuitry.
 7. The method of claim 6, wherein theaggregate noise floor metric value for each channel in the rankedchannel list is further determined to account for a gain profile anddirection of the antenna assembly.
 8. The method of claim 6, furthercomprising: selecting an available channel from the ranked channel listfor wireless communications; and engaging in wireless communicationsusing the selected channel.
 9. The method of claim 8, wherein theelectronic device transmits the spectrum access request and makes thechannel selection as background operations without involvement of auser.
 10. The method of claim 6, wherein the noise from the radiofrequency devices includes predicted noise floor from primary channeland out-of-band emissions of high-power protected transmitters.
 11. Aspectrum access assistance server that hosts a spectrum access functionfor electronic devices, the electronic devices each having communicationcircuitry with a corresponding adjacent channel blocking profile;comprising: communications circuitry configured to communicate with theelectronic devices and receive a spectrum access request from arequesting one of the electronic devices, the spectrum access requestincluding a location of the electronic device; and a controller thatexecutes logical operations to generate an available channel list rankedby respective aggregate noise floor metric values for the electronicdevice and transmit the available channel list to the electronic deviceover the communications circuitry, the aggregate noise floor metricvalue for each channel in the ranked channel list determined to accountfor the location of the electronic device, noise from radio frequencydevices, and the adjacent channel blocking profile of the communicationscircuitry of the electronic device.
 12. The spectrum access assistanceserver of claim 11, wherein the aggregate noise floor metric value foreach channel in the ranked channel list is further determined by theserver to account for a gain profile and direction of an antennaassembly of the requesting electronic device.
 13. The spectrum accessassistance server of claim 11, wherein the noise from the radiofrequency devices includes predicted noise floor from primary channeland out-of-band emissions of high-power protected transmitters.